INTERNATIONAL INSTITUTE
OF BIOPHYSICS
Conference
on Biophotons 1999
Abstracts of the Conference Reports in
alphabetic Order
REGULATION OF THE OXIDATIVE BURST IN MOUSE PERITONEAL NEUTROPHILS
BY APPLICATION OF WEAK MAGNETIC FIELDS.
V.V. Lednev, N.A.Belova, M.M. Potselueva, I.S. Yurkov.
Institute of Theoretical and Experimental Biophysics, Russian Academy
of Sciences, Pouschino, Moscow Region, 142292, Russia. Fax: 7(0967) 790553,
E-mail: lednev@leda.iteb.serpukhov.su
Background. It is known, that generation of reactive oxygen species
(ROS) in neutrophils stimulated by phorbol esters or phormyl peptides proceeds
via a protein kynase C (PKC) dependent pathway. On the other hand, there
are indications that weak magnetic fields (MF) exert their action on biosystems
affecting the activity of some Ca2+-dependent enzymes, and in
particular that of PKC. Therefore we studied the possibility to influence
the rate of ROS-generation in neutrophils exposing them to weak MF known
to influence the PKC-dependent bioprocesses.
Methods. Suspensions of the zimosan-elicited peritoneal neutrophils
(mouse, NMRI-strain, females, 20-25 g b.w.) were prepared according to
standard method.. Each of the experimental and control glass test-tubes
contained 0.5 ml suspension of cells in Hank's solution at concentration
of about 106 cells/ml, luminol - 10-5M and the stimulating
agent - phorbol 12-myristate 13-acetate (PMA), or N-formyl-methionyl leucyl-phenylalanine
(fMLP) - at concentrations 10-8-10-7M. The rate of
ROS-generation was monitored with the use of a single-channel chemiluminoneter
at room temperature. In most experiments 3 test-tubes were placed both
in control and experimental MF. The intensity of chemiluminescense in test-tubes
was measured every two minutes. The duration time of a single measurement
was 15 sec. Control test-tubes were exposed to the ambient static MF, while
the experimental - to the MFs of two types: (1) Ca2+-tuned combined
magnetic field (Ca2+-CMF) and (2) pulsed magnetic field (PMF),
composed of the trains of 199 short pulses with an amplitude 100 T repeated
with 1.5 Hz - frequency.
Results and Discussion. Exposure of PMA-activated neutrophils
to Ca2+-CMF is accompanied by a decrease in the rate of ROS-generation
by 50-70%. However, the same field produced an increase of ROS-generation
by 40-50% in the fMLP-activated neutrophils. PMF also changes the rate
of ROS-generation by about 50%, but the signs of the effects observed in
this case (for the same preparations) were the opposite to those induced
by Ca2+-CMF. These results indicate the possibility of substantial
modulation of the ROS-generation by neutrophils under the influence of
weak MF. The sign of effects (activation or inhibition) depends both on
the type of stimulating agent used and on the type of MF applied. The data
obtained in experiments with PMA-activated neutrophils confirm, although
indirectly, the hypothesis, according to which the change in PKC-activity
may be the primary event in the interaction of MF with biosystems. Dependence
of the sign of effect on the type of stimulus may be explained in terms
of the negative feedback interaction between the activities of phospholipase
C and PKC in fMLP - stimulated neutrophils.
© International
Institute of Biophysics 2001 E-mail: iib@lifescientists.de
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